596-75-8Relevant academic research and scientific papers
Method for preparing Guerbet acids by taking malonate as raw material
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Paragraph 0024, (2017/08/29)
The invention discloses a method for preparing Guerbet acids by taking malonate as a raw material. The method comprises the following steps: using the malonate as the raw material, and carrying out alkylation reaction under the action of alkali to obtain dialkyl malonate; sequentially carrying out hydrolysis reaction and decarboxylic reaction on obtained dialkyl malonate to obtain the Guerbet acid, wherein the malonate is dimethyl malonate or diethyl malonate; the alkali of the alkylation reaction is selected from one or more of potassium carbonate, sodium hydroxide, potassium hydroxide, sodium methylate and sodium ethoxide; an alkylating reagent is haloalkane with 2 to 20 carbons. According to the method disclosed by the invention, the Guerbet acids are prepared by taking the malonate as the raw material for the first time; related three reactions are easily operated, high temperature or high pressure is not needed, and high yield is realized; by means of the alkylation reaction disclosed by the invention, a main chain structure and a branched chain structure of the Guerbet acids can be flexibly regulated and controlled, and further the Guerbet acids with different properties are obtained.
Iron-catalyzed, hydrogen-mediated reductive cyclization of 1,6-enynes and diynes: Evidence for bis(imino)pyridine ligand participation
Sylvester, Kevin T.,Chirik, Paul J.
supporting information; experimental part, p. 8772 - 8774 (2009/12/04)
(Chemical Equation Presented) The bis(imino)pyridine iron dinitrogen complex (iPrPDI)Fe(N2)2 catalyzes the hydrogen-mediated reductive cyclization of enynes and diynes with turnover frequencies comparable to those of established precious metal catalysts. Amino, oxygenated, and carbon-based substrates are readily cyclized to the corresponding hetero- and carbocycles with 5 mol % iron and 4 atm H2 at 23°C. Stoichiometric reactions between selected substrates and the iron compound under a N2 atmosphere established transfer dehydrogenation from an isopropyl aryl substituent to either the enyne or diyne substrate. In situ monitoring of the catalytic reaction by 1H NMR spectroscopy coupled with deuterium labeling experiments established rapid cyclization followed by turnoverlimiting hydrogenation. Copyright
Synthesis of 3-alkyl(aryl)thietanes
Shevchenko,Volynskii
body text, p. 123 - 128 (2010/02/28)
A preparative procedure for the synthesis of thietanes bearing alkyl substituents in the β-position was developed. Using this procedure, 3-substituted thietanes can be obtained in four steps with an ultimate yield of > 50%. 3-R-thietanes (where R = CH3, C4H9, C5H11, C6H13, C6H 5) and the corresponding sulfoxides and sulfones were synthesized and examined. The feasibility of preparation of gem-3,3-substituted thietanes was exemplified by the synthesis of 3,3-dihexylthietane.
Synthesis and Properties of New Lipophilic Macrotricyclic Cylindrical Cryptands
Quici, Silvio,Manfredi, Amedea,Raimondi, Laura,Sironi, Angelo
, p. 6379 - 6388 (2007/10/03)
Cylindrical cryptands 2a-c, in which two 1,7-dioxa-4,10-diazacyclododecane rings are connected by two equally substituted propylene bridges, have been obtained in appreciable yields by a ''one-pot'' synthesis.The assembling of the macrotricyclic structure is likely driven by the template effect of metal cations.These compounds, both as free receptors or as complexes, exist as cis and trans diastereoisomers, which do not interconvert and have been separated and characterized by X-ray analysis.The extraction constants (Ke) of cryptands 2 for alkali picrates under CHCl3/H2O and solid/liquid two-phase conditions have been measured by UV-vis spectrophotometry.The complexation behavior of cryptands 2 has been rationalized analyzing the preorganization of binding sites in the minimum energy conformations obtained by molecular mechanics calculations.Minimum energy conformations have been calculated also for the previously reported cryptands 1 and have been compared with those of 2.Results fit reasonably well with those of X-ray structures.
Role of Substituents in Copper(II) Extraction with N,N'-Bis(8-quinolyl)malonamides
Hirose, Takuji,Hiratani, Kazuhisa,Kasuga, Kazuyuki,Saito, Kiyoshi,Koike, Tohru,et al.
, p. 2679 - 2684 (2007/10/02)
It has been found that substituents on N,N'-bis (8-quinolyl)malonamide play an important role in copper(II) extraction: among the substituents studied, benzyl groups dramatically increased extractability of the malonamide complex.The role of substituents is discussed on the basis of the results of titration and 1H NMR measurements of copper(II) or nickel(II) complexes as well as copper(II)-extraction experiments.Intramolecular interactions between ? electrons of the benzyl group and the metal centre of the complex are proposed to occur.
Molecular Ribbons from Molecular Recognition directed Self-assembly of Self-complementary Molecular Components
Lehn, Jean-Marie,Mascal, Mark,DeCian, Andre,Fischer, Jean
, p. 461 - 468 (2007/10/02)
The programmed self-association of the self-complementary nucleotide-like pyrimidinone 5 and pyrimidinedione 6, generates, as predicted, organized supramolecular ribbons.The crystal structure of such a species has been determined.A similar entity is obtained from the pyrimidinetriamine 12 with solvent participation, giving a quadruply hydrogen-bonded ribbon, whose crystal structure has also been determined.These processes give access to the designed generation of organized arrays of functional substituents.
Substituent effects on partition coefficients of barbituric acids
Wong,McKeown
, p. 926 - 932 (2007/10/02)
Precise partition coefficients in 1-octanol-water at 25°C were determined for three 2-thiobarbituric acids and 14 barbituric acids with a wider range of substituents. The experimental log P values (log P(exp)) of barbituric acids were correlated with the carbon number and the branching effect of the C5 substituent(s) by linear regression analysis. The carbon number term makes a major contribution to the partition coefficients. The contribution of the polar effect of the C5 substituents was insignificant in contrast to a previous report. Hydrophobic constants (π) were determined for allyl, phenyl, and chloro-substituents, and these emperical π values gave much closer predicted calculated log P (log P(calc)) values when applied to the reported log P(exp) values.
Alkylation Reactions of Ethyl Malonate, Ethyl Acetoacetate, and Acetylacetone by Gas-Liquid Phase-Transfer Catalysis (G.L.-P.T.C)
Tundo, Pietro,Venturello, Paolo,Angeletti, Enrico
, p. 2159 - 2162 (2007/10/02)
Malonyl, acetoacetyl, and acetylacetonyl alkylation reactions have been carried out in the gaseous state under gas-liquid phase-transfer catalysis (g.l-p.t.c) conditions using potassium carbonate or sodium hydrogencarbonate as the base.No alkali metal was used to generate the reactive anion.No solvents are used in the process, and the reaction mixture requires no stirring.The phase-transfer catalysts which promote the reaction: phosphonium salts, crown ethers, and poly(ethylene glycol) are also the medium in which the reaction occurs; they direct C- or O- alkylation, as a function of the methylene compound and the alkylating agent used.The malonic ester alkylation using poly(ethylene glycol) gives rise to improved selectivity for C-monoalkylation compared with the other catalysts.
Ring-Closure Reactions. 22. Kinetics of Cyclization of Diethyl (ο-Bromoalkyl)malonates in the Range of 4- to 21-Membered Rings. Role of Ring Strain
Casadei, Maria Antonietta,Galli, Carlo,Mandolini, Luigi
, p. 1051 - 1056 (2007/10/02)
The kinetics of closure of 1,1-bis(ethoxycarbonyl)cycloalkanes from the anions derived from diethyl (ο-bromoalkyl)malonates have been investigated in Me2SO at 25 degC.Rate constants and effective molarities (EM) have been obtained for the ring sizes 4-13, 17, and 21.This is the first quantitative study on the kinetics of SN2 closure of all-carbon rings, which includes small, common, medium and large rings.The reactivity data span over nine powers of ten, which is the widest reactivity range recorded so far in a cyclization series.Due to the extremely low EM for the 9-, 10-, and 11-membered rings, a special competition technique was developed for these rings.Comparison of the present results with literaturee data on SN2 ring-closure reactions reveals structure-dependent reactivity patterns showing varying features, which are qualitatively accounted for on the basis of structure effects on transition-state strain energies.A dissection of the EM data for the malonate cyclization into strain and probability factors was attempted.Perhaps the most interesting result is a definite tendency for transition-state strain energies to parallel cycloalkane strain energies for the 7-membered and larger rings but not for the smaller rings.In the latter cases the ring product no longer appears to be a proper model for comprehending the transition state.
